This invention relates generally to pivot joints, and in particular to a pivot joint useful for connecting a headlamp adjuster to a reflector inside a headlamp assembly or an external reflector and lens headlamp assembly. The improved ball socket can be used effectively with disengageable ball stud or conventional spherical, semi-spherical or xe2x80x9cearedxe2x80x9d ball studs.
Pivotable spherical joints, commonly referred to as ball joints, include a ball stud engaged in a socket. Such joints have a wide variety of applications where a pivotable connection between two parts is desirable. For example, they may be used in many types of linear actuators and have been found to be particularly useful in automotive lamp assemblies. As seen in U.S. Pat. No. 5,707,133, the disclosure of which is incorporated herein by reference, automotive lamp assemblies used as headlights typically comprise several basic parts: a support frame, a reflector, a lens, a bulb, and one or more adjusters.
In the automotive lamp assembly example, the support frame houses the reflector and the bulb on a pivotable mounting to allow the aim of the light to be adjusted using the adjuster. The lens seals the front of the assembly to protect it from the elements assailing the front end of the vehicle and provides an aerodynamic shape and attractive appearance. The reflector mounts inside the housing on one fixed ball joint and is adjustable horizontally and vertically using adjusters that interface with the reflector through moving ball joints. The moving ball joints are moveable by actuating the adjusters connected to the moving ball joints by a ball stud having a head and a shaft. Another type of automotive headlamp assembly that uses linear actuators is shown in U.S. Pat. No. 5,360,282. In this type of headlamp assembly the linear actuator is mounted to a bracket and the ball joint end supports a reflector, lens and light bulbs. This type of application requires a higher strength ball joint due to the additional weight being supported. In particular, pull-out strength of the ball joint needs to be greater to withstand vibration.
While one possible application of the present invention is in headlamp assemblies, other applications are possible and references to use in a headlamp assembly should not be deemed to limit the application of the present invention. Additionally, while the improved ball socket design described herein may be used with a disengageable ball stud, such as the one described in U.S. Pat. No. 6,113,301, the disclosure of which is incorporated by reference, it can also be used advantageously with ball studs having xe2x80x9cearsxe2x80x9d or engaging tabs or semi-spherical ball stud designs. Examples of such adjusters are disclosed in U.S. Pat. Nos. 4,689,725 and 5,186,531, an example of an xe2x80x9cearedxe2x80x9d ball stud is shown in FIG. 13, and an example of a semi-spherical ball stud is shown in FIG. 12.
Conventional ball joints for use in automotive lamp assemblies typically include a ball stud with a spherical engagement head extending from an adjuster. The ball stud is moveable linearly in and out of the adjuster. Examples of such ball studs and corresponding sockets are shown in FIGS. 4 and 5 of U.S. Pat. No. 4,689,725; FIG. 1 of U.S. Pat. No. 5,673,992; FIG. 2 of U.S. Pat. No. 5,095,411; and FIGS. 10-14 of U.S. Pat. No. 5,186,532. Additionally, several U.S. Patents disclose ball joints for use in headlamp adjusting mechanisms: 4,974,123, 5,047,904, and 5,063,481.
As is known in the art, ball studs interface with a plastic socket 20, such as the one shown in FIGS. 1 and 2 and in U.S. Pat. No. 5,653,548. The sockets 20 are attached to the reflector such that movement of the ball stud effectuates movement of the reflector. For example, socket 20 is attached to a boss 30 with a fastener 31. Boss 30 has an aperture 32 therein for receiving the fastener 31. The interface between the ball stud (not shown) and the socket 20 is such that the head of the ball stud cannot be readily removed from the socket 20 once the head is disposed therein. This is because fingers or tabs 22 point inwardly toward socket cup 24 at approximately a forty-five degree angle to retain the head in socket 20. The ball stud head cannot be allowed to slip from socket 20 once the adjuster is installed, or the adjuster will not be able to adjust the orientation of the reflector. When engaged in socket 20, the ball stud head is free to pivot within the socket cup 24 of socket 20.
While functionally quite effective, there is at least one shortcoming to using ball studs in conventional xe2x80x9ctabbedxe2x80x9d sockets. This shortcoming is that the head 22 can be pulled out of socket 20 under certain conditions of operation, such as vibration while supporting heavier reflectors or in heavier headlamp assemblies like the one previously referenced in U.S. Pat. No. 5,360,282, leaving the adjuster non-operational. This unexpected pull-out generally occurs because tabs 22 are flexible. Tabs 22 must be flexible enough to allow the head to be inserted into socket 20, while at the same time resist pull-out. Though pull-out of the ball stud is resisted to some degree of success, if enough pull-out force is applied, the tabs 22 deflect downward toward the socket cup 24 and the ball stud head xe2x80x9cpops out.xe2x80x9d Reducing the flexibility of tabs 22 is not an option because it would either be to difficult to insert the ball stud head into socket 20, or the elasticity of the tabs 22 would be lessened to the degree that they would break off during insertion of the ball stud.
Accordingly, the need exists for an improved ball socket that securely retains a ball stud placed therein, can be effectively used in connection with disengageable or conventional ball studs, is cost effective, and resists accidental pull-out. The present invention relates to an improved ball joint which is capable of being used in automotive lamp assemblies and solves the problems raised or not solved by existing ball joints. Of course, the present invention may be used in a multitude of non-automotive lamp situations where similar performance capabilities are required.
The present invention provides a ball socket that is cost-effective, easily installed in the lamp, securely retains a ball stud placed therein, and can be effectively used in connection with disengageable or conventional ball studs. Further, ball studs can be selectively inserted and removed from the corresponding socket as desired, yet greatly resist accidental pull-out of the ball stud.
The ball socket for use with a ball stud and a mounting screw is generally constructed so that the socket has a face plate having an opening for receiving the ball stud, and a combination of support legs and arms extending from the face plate to form a socket cup for receiving the ball stud. The ball socket includes a socket body having a socket cup with an undercut portion defining a chamber. This chamber is designed to hold the head of a mounting screw. A mounting screw having a head may be placed in the chamber of the socket, yet still rotate for attachment purposes. The arms extend from the face plate to the opposite end of the socket, near the undercut portion. The arms have an upper portion, middle portion and a bottom portion. During insertion of the ball stud into the socket cup, at least the upper portion and middle portion of each arm deforms.
The ball socket may be used in a headlamp assembly. Generally, the headlamp assembly is composed of a reflector having a boss and a ball socket mounted to the boss by a mounting screw. The ball socket has an opening for receiving a ball stud into the adjacent socket cup having several arms. The headlamp adjuster has a ball stud extending therefrom, which is engaged in the ball socket.
The ball socket can accept different types of ball studs, either conventional or disengageable. The ability to use the socket with a wide variety of ball studs provides a significant benefit to headlamp assemblers because it allows the use of one style of socket with a number of types of ball stud.
While one possible application of the present invention is in headlamp assemblies, many other applications are possible and references to use in a headlamp assembly should not be deemed to limit the uses of the present invention. The terms xe2x80x9cball stud,xe2x80x9d xe2x80x9cengagement head,xe2x80x9d or xe2x80x9cheadxe2x80x9d as used herein should not be interpreted as being limited to spherical or semispherical shapes, rather, the engagement heads of ball studs in accordance with the present invention may have a wide variety of shapes and may include protrusions having semispherical or otherwise pivotably-shaped tips. The arms used in the socket can be a wide variety of shapes capable of selectively retaining the ball stud in the socket. These and other objects and advantages of the present invention will become apparent from the detailed description, claims, and accompanying drawings.
FIG. 1 is a perspective view of a prior art socket shown in relation to a mounting screw and mounting boss;
FIG. 2 is a cross-section of the prior art socket shown in FIG. 1 taken generally along the line 2xe2x80x942;
FIG. 3 is a perspective view of one embodiment of a socket in accordance with the present invention;
FIG. 4 is an end elevation of the socket shown in FIG. 3;
FIG. 5 is a bottom cross-section of the socket shown in FIG. 3 taken generally along the line 5xe2x80x945 in FIG. 4;
FIG. 6 is a side elevational view of the socket shown in FIG. 3;
FIG. 7 is a side cross-sectional view of the socket shown in FIG. 3 taken generally along the line 7xe2x80x947 in FIG. 4;
FIG. 8a is a schematic side view of a ball stud prior to insertion into a socket in accordance with the invention as shown in FIG. 3;
FIG. 8b is a schematic side view of a ball stud during insertion into a socket in accordance with the invention as shown in FIG. 3;
FIG. 8c is a schematic side view of a ball stud after insertion into a socket in accordance with the invention as shown in FIG. 3;
FIG. 9 is a schematic diagram showing the forces exerted on the socket as a ball stud is pulled from a seated position within a socket in accordance with the present invention;
FIG. 10 is a perspective view of an alternative embodiment of the present invention having a peanut-style extension;
FIG. 11 is a perspective view of a disengagable ball stud;
FIG. 12 is a perspective view of a semi-spherical ball stud;
FIG. 13 is a perspective view of a ball stud with ears; and
FIG. 14 is a partial cross-section of an automotive lamp assembly having a socket constructed in accordance with one embodiment of the present invention installed to a reflector.